⏰ Cron Expression Parser
Parse and understand any cron expression instantly. Get a human-readable description and see the next 10 scheduled run times. Build cron schedules with presets for common patterns.
Frequently Asked Questions
What is a cron expression?
A cron expression is a 5-field string defining when a scheduled task runs: minute hour day-of-month month day-of-week. Special characters: * (any value), , (list), - (range), / (step). Example: 0 9 * * 1-5 runs at 9:00 AM every weekday.
What does */15 mean in cron?
*/15 means "every 15 units." In the minute field it runs at :00, :15, :30, :45. In the hour field it runs every 15 hours. The * means start from the minimum value; the /15 is the step interval.
How do I schedule a cron job on the last day of every month?
Some cron implementations support the L character for "last" — e.g. 0 0 L * *. Standard Unix cron doesn't support L; instead, use a script that checks whether tomorrow is the 1st: 0 0 28-31 * * [ "$(date -d tomorrow +%d)" = "01" ].
What is the difference between cron minute field 0 vs */1?
0 in the minute field means "only at minute 0" — i.e., the top of every hour. */1 means "every 1 minute" — every minute of every hour. These are completely different schedules. Always double-check which field you're editing.
Online Cron Expression Parser — Understand Any Crontab Schedule
Cron is the time-based job scheduler built into Unix-like operating systems. Used by system administrators, DevOps engineers, and backend developers to automate recurring tasks — backups, report generation, cache clearing, email digests — cron expressions can be tricky to read at a glance.
Cron in Modern Infrastructure
Beyond classic Unix crontab, cron expressions are used in Kubernetes CronJobs, AWS EventBridge Scheduler, GitHub Actions schedules, Laravel task scheduling, and most CI/CD pipelines. Understanding cron syntax is a core DevOps skill.
Common Pitfalls
Day-of-month and day-of-week interact differently across implementations. Some tools use 0–6 (Sunday=0), others use 1–7 (Sunday=1). AWS and Quartz use 6-field expressions with a seconds field prepended. Always validate your expression before deploying to production.